An API (application programming interface) uses a collection of software functions and procedures, referred to as API calls, that can be executed by other software applications. Service providers (e.g., telecommunications providers) may provide APIs that vendors can use to access services/features that are included in software products that vendors may eventually offer to consumers (e.g., end users).
In wireless data plans, data usage for end users is typically charged to an account associated with each end user. The end user account may have a periodic limit on total data usage, for example on wireless networks (e.g., a 2 Gigabyte per month data plan). End users on networks that have periodic limits for data usage often arrange their data usage behavior to avoid overages associated with periodic limits on data usage. Toll-free data services allow service providers to charge certain types of data usage by end users to third-party vendors, thus allowing end users to access certain content without concern for overages.